Atherectomy device

ABSTRACT

An atherectomy device for removing deposits such as plaque from an interior of a vessel including an outer member and a rotatable shaft positioned for rotational movement within the outer member and fixed axially within the outer member. A tip is mounted to the distal region of the rotatable shaft and is positioned distally of the distal end of the outer member to create a gap between the proximal end of the rotatable tip and the distalmost edge of the outer member. The rotatable tip has a longitudinal axis mounted to the rotatable shaft for rotation about its longitudinal axis upon rotation of the shaft, the shaft including a guidewire lumen for receiving a guidewire to enable over the wire insertion of the device.

This application claims priority from provisional application62/097,049, filed Dec. 27, 2014, the entire contents of which areincorporated herein by reference.

BACKGROUND Technical Field

This application relates to a vascular surgical apparatus, and moreparticularly to a minimally invasive device for removing plaque or otherdeposits from the interior of a vessel.

Background of Related Art

The vascular disease of atherosclerosis is the buildup of plaque orsubstances inside the vessel wall which reduces the size of thepassageway through the vessel, thereby restricting blood flow. Suchconstriction or narrowing of the passage in the vessel is referred to asstenosis. In the case of peripheral vascular disease, which isatherosclerosis of the vascular extremities, if the vessel constrictionis left untreated, the resulting insufficient blood flow can causeclaudication and possibly require amputation of the patient's limb. Inthe case of coronary artery disease, if left untreated, the blood flowthrough the coronary artery to the myocardium will become inadequatecausing myocardial infarction and possibly leading to stroke and evendeath.

There are currently several different treatments for treating arterialdisease. The most invasive treatment is major surgery. With peripheralvascular diseases, such as occlusion of the tibial artery, major surgeryinvolves implantation and attachment of a bypass graft to the artery sothe blood flow will bypass the occlusion. The surgery involves a largeincision, e.g., a 10 inch incision in the leg, is expensive and timeconsuming for the surgeon, increases patient pain and discomfort,results in a long patient recovery time, and has the increased risk ofinfection with the synthetic graft.

Major surgery for treating coronary artery disease is even more complex.In this surgery, commonly referred to as open heart surgery, a bypassgraft connects the heart to the vessel downstream of the occlusion,thereby bypassing the blockage. Bypass surgery requires opening thepatient's chest, is complex, has inherent risks to the patient, isexpensive and requires lengthy patient recovery time. Bypass surgeryalso requires use of a heart lung machine to pump the blood as the heartis stopped, which has its own risks and disadvantages. Oftentimes, thesaphenous vein in the patient's leg must be utilized as a bypass graft,requiring the additional invasive leg incision which further complicatesthe procedure, increases surgery time, lengthens the patient's recoverytime, can be painful to the patient, and increases the risk ofinfection.

Attempts to minimize the invasiveness of coronary bypass surgery arecurrently being utilized in certain instances. These typically includecreating a “window approach” to the heart. Although the window approachmay reduce patient trauma and recovery time relative to open heartsurgery, it still requires major surgery, and is a complicated anddifficult surgery to perform due to limited access and limitedinstrumentation for successfully performing the operation. Attempts toavoid the use of a heart lung machine by using heart stabilizationmethods has become more accepted, but again, this does not avoid majorsurgery.

Due to the invasiveness and potential for complications with majorperipheral or coronary vascular surgery, minimally invasive procedureshave been developed. Balloon angioplasty is one of the minimallyinvasive methods for treating vessel occlusion and obstructions. Acatheter having a balloon is inserted through the access artery, e.g.,the femoral artery in the patient's leg or the radial artery in the arm,and advanced through the vascular system to the occluded site over aguidewire. The deflated balloon is placed at the occlusion and inflatedto crack and stretch the plaque and other deposits to expand the openingin the vessel. Balloon angioplasty, especially in coronary surgery, isfrequently immediately followed by insertion of a stent, a smallmetallic expandable device which is placed inside the vessel wall toretain the opening which was created by the balloon. Balloon angioplastyhas several drawbacks including difficulty in forcing the balloonthrough the partially occluded passageway if there is hard occlusion,the risk involved in cutting off blood flow when the balloon is fullyinflated, the frequency of restenosis after a short period of time sincethe plaque is essentially stretched or cracked and not removed from thevessel wall or because of the development of intimal hyperplasia and thepossibility of balloon rupture when used in calcified lesions.

Another minimally invasive technique used to treat arteriosclerosis isreferred to as atherectomy and involves removal of the plaque by acutting or abrading instrument. This technique provides a minimallyinvasive alternative to the bypass surgery techniques described aboveand can provide an advantage over balloon angioplasty methods in certaininstances. Atherectomy procedures typically involve inserting a cuttingor ablating device through the access artery, e.g., the femoral arteryor the radial artery, and advancing it over a guidewire through thevascular system to the occluded region, and rotating the device at highspeed to cut through or ablate the plaque. The removed plaque ormaterial can then be suctioned out of the vessel or be of such finediameter that it is cleared by the reticuloendothelial system. Removalof the plaque in an atherectomy procedure has an advantage over balloonangioplasty plaque displacement since it debulks the material.

Examples of atherectomy devices in the prior art include U.S. Pat. Nos.4,990,134, 5,681,336, 5,938,670, and 6,015,420. These devices haveelliptical shaped tips which are rotated at high speeds to cut away theplaque and other deposits on the interior vessel wall. A well-knowndevice is marketed by Boston Scientific Corp. and referred to as theRotablator. As can be appreciated, in these devices, the region ofplaque removal is dictated by the outer diameter of the cutting tip(burr) since only portions of the plaque contacted by the rotating tipare removed. The greater the area of plaque removed, the largerpassageway created through the vessel and the better the resulting bloodflow.

U.S. Pat. Nos. 5,217,474 and 6,096,054 disclose expandable cutting tips.These tips however are quite complex and require additional expansionand contraction steps by the surgeon.

U.S. Pat. No. 6,676,698 discloses an atherectomy device designed toobtain an optimal balance between the competing objectives of thesmallest introducer sheath size to facilitate insertion and reducetrauma to the vessel and the largest atherectomy tip size to remove alarger region of plaque or other deposits from the vessel wall.

However it would be advantageous to enhance the breaking up and removalof the small particles in atherectomy procedures.

SUMMARY

The present invention provides in one aspect an atherectomy device forremoving deposits such as plaque from an interior of a vessel comprisingan outer member having a distal end, a rotatable shaft positioned forrotational movement within the outer member and fixed axially within theouter member and having a longitudinal axis, a distal region and adistalmost edge, and a rotatable tip having a proximal end and a distalend. The proximal end of the rotatable tip is positioned distally of thedistal end of the outer member to create a gap between the proximal endof the rotatable tip and the distalmost edge of the outer member. Therotatable tip is mounted to the distal region of the rotatable shaft.The rotatable tip has a longitudinal axis and is mounted to therotatable shaft for rotation about its longitudinal axis upon rotationof the shaft, the shaft including a guidewire lumen for receiving aguidewire to enable over the wire insertion of the device.

In some embodiments, the device includes an auger positioned on therotatable shaft, the auger positioned proximally of the rotatable tipand distally of a distalmost edge of the outer member, wherein rotationof the shaft rotates the auger to move particles abraded by the tipproximally into the outer member.

In some embodiments, particles are aspirated through the outer member inthe space between the rotatable shaft and an inner wall of the outermember.

In some embodiments, the rotatable tip has a scalloped region at anintermediate region. In some embodiments, the rotatable tip is made offirst and second materials, the first material having a first densityand the second material having a second density less than the firstdensity. In some embodiments, the material of a first density is on oneside of the tip and the material of the second density is on the otherside of the tip. Examples of materials include tungsten carbide andaluminum. In some embodiments, the rotatable tip has a first region onone side of a longitudinal axis of the shaft and a second region on anopposing side of the longitudinal axis of the shaft, and the firstregion has a cutout so a first amount of material in the first region isless than a second amount of material in the second region.

In some embodiments, the rotatable tip can be mounted proximal of thedistalmost edge of the rotatable shaft.

The tip can have a lumen extending therethrough dimensioned to receivethe rotatable shaft.

In some embodiments, the rotatable tip is composed of first and secondcomponents, e.g., halves, the components radially spaced from eachother. In some embodiments, the first component is composed of amaterial having a density greater than a density of the secondcomponent. In some embodiments, the first component has a portionremoved so it is composed of less material than the second component.

In accordance with another aspect of the present disclosure, anatherectomy device for removing deposits such as plaque from an interiorof a vessel is provided comprising an outer member having a distal end,a rotatable shaft positioned for rotational movement within the outermember and fixed axially within the outer member and having alongitudinal axis, a distal region and a distalmost edge. A rotatabletip has a proximal end and a distal end, the proximal end positioneddistally of the distalmost edge of the outer member to create a gapbetween the proximal end of the rotatable tip and the distalmost edge ofthe outer member. The rotatable tip is mounted to the distal region ofthe rotatable shaft and has a longitudinal axis and is mounted to therotatable shaft for rotation about its longitudinal axis upon rotationof the rotatable shaft. The rotatable shaft includes a guidewire lumenfor receiving a guidewire to enable over the wire insertion of thedevice. The rotating tip has a first portion and a second portion, thefirst portion being different than the second portion.

In some embodiments, the device further includes an auger positioned onthe rotatable shaft, the auger positioned proximally of the rotatabletip and extending along the rotatable shaft, wherein rotation of therotatable shaft rotates the auger to move particles macerated by therotatable tip proximally into the outer member.

In accordance with another aspect of the present disclosure a method forremoving deposits such as plaque from an interior of a vessel isprovided. The method comprises the steps of:

-   -   providing an introducer sheath having an internal diameter;    -   providing a deposit removal device including an outer member, a        rotatable shaft and a rotating tip at a distal portion of the        shaft, the rotating tip having a first portion and a second        portion, the first portion being different than the second        portion, the tip having a transverse cross-sectional dimension;    -   inserting the introducer sheath through a skin incision and into        a vessel,    -   advancing the tip adjacent the deposits to be removed; and    -   actuating a motor to rotate the tip at high speed to contact and        remove the deposits, the tip rotating to remove deposits in a        cross-sectional area greater than the transverse cross-sectional        dimension of the tip.

The method can in some embodiments further include the step ofaspirating deposits through a space in the outer member between theshaft and an inner wall of the outer member. The rotatable shaft canhave a screw thread so the step of rotating the shaft causes theexternal screw thread of the shaft to direct particles proximally.

The method in some embodiments further includes the step of applying avacuum to aspirate proximally deposits removed by rotational movement ofthe tip.

In some embodiments, the device includes an outer member and the shaftis rotatably positioned within the outer member and particles areaspirated in a gap between an outer diameter of the shaft and an innerdiameter of the outer member.

The method can further include the step of inserting the tip and shaftover a guidewire.

In some embodiments, the first and second portions differ by the firstportion having a cutout to remove material from the first portion. Insome embodiments, the first and second portions differ by the firstportion having a first density and the second portion having a seconddensity less than the first density.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiment(s) of the present disclosure are described hereinwith reference to the drawings wherein:

FIG. 1 is a perspective view of the distal portion of the atherectomydevice of one embodiment of the present invention;

FIG. 2 is a cross-sectional view of the distal portion of theatherectomy device of FIG. 1 ;

FIG. 3 is a view similar to FIG. 2 showing aspiration through thecatheter;

FIG. 3A is a transverse cross-sectional view of the tip of FIG. 1 ;

FIG. 4 is a partial cross-sectional view of the distal portion of analternate embodiment of the atherectomy device of the present invention;

FIG. 5 is a cut away side view of the atherectomy bit of FIG. 4 ;

FIG. 6 is a transverse cross-sectional view taken along line 6-6 of FIG.5 ;

FIG. 7 is a cut away side view of the bit of FIG. 4 showing the oppositeside of the side shown in FIG. 5 ;

FIG. 8 is a transverse cross-sectional view taken along line 8-8 of FIG.7 ;

FIG. 9 is a perspective view of a distal portion of another alternateembodiment of the atherectomy device of the present invention;

FIG. 10A is a transverse cross-sectional view of the bit of FIG. 4 ;

FIG. 10B is a view similar to FIG. 10A showing an alternate embodimentof the atherectomy bit of the present invention;

FIG. 11A is perspective view of a distal portion of another alternateembodiment of the atherectomy device of the present invention;

FIG. 11B is a longitudinal cross-sectional view of the device of FIG.11A;

FIGS. 12A-12D show a method of use of the atherectomy device of FIG. 4wherein:

FIG. 12A is a side view in partial cross-section of the guidewire beinginserted through the vessel;

FIG. 12B is a side view in partial cross-section illustrating therotating shaft and bit of the atherectomy device inserted over theguidewire;

FIG. 12C is a view similar to FIG. 12B showing rotation of the shaft toremove plaque;

FIG. 12D is a view similar to FIG. 12C showing further removal of theplaque; and

FIG. 13 is a schematic view illustrating the atherectomy system of oneembodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention is directed to an atherectomy device designed forhigh speed rotation to remove plaque or other deposits on the insidewall of the vessel to widen the blood passageway therethrough. Toachieve such rotation, the atherectomy tip is positioned at a distal endof a flexible rotating shaft that can be gas or electrically powered.The shaft rotates at high speed, typically between 100,000 and 200,000rpm, causing the cutting or ablation surface of the tip to remove theplaque and deposits to which it comes into contact. The atherectomydevice of the present invention has application in a variety of vesselssuch as the coronary arteries, peripheral vessels such as the tibialartery, femoral, and popliteal, and saphenous vein bypass grafts.

In order for the atherectomy tip to reach the vessel stenosis(obstruction) it is supported on a flexible shaft and inserted alongwith the flexible shaft through an introducer sheath and over aguidewire. More specifically, the introducer sheath is placed through askin incision and into a vessel, e.g., the femoral artery in thepatient's leg, to provide access to the target site. A guidewire is theninserted through the introducer sheath and advanced through theappropriate vessels to the target obstructed site, typically thecoronary artery. The flexible shaft and attached atherectomy tip arethen inserted through the introducer sheath and threaded over the lengthof the guidewire to the target obstructed site. Actuation of the motorspins the shaft and tip so the cutting surface repeatedly comes intocontact with the obstruction, e.g., plaque, to remove it from the vesselwall.

Details of the present invention will now be described with reference tothe drawings wherein like reference numerals identify similar or likecomponents throughout the several views.

FIG. 1 illustrates one embodiment of the atherectomy device of thepresent invention, designated generally by reference numeral 10. Theentire device is shown in FIG. 13 ; the distal portion of the device isshown in FIGS. 1-3 . The atherectomy tip or bit 12 of the device 10 isconnected to a flexible inner shaft 20 such that rotation of the innershaft 20 rotates the tip 12. As shown, the tip 12 is connected at adistal region of the rotatable shaft 20, but preferably spaced from adistalmost end 22 of inner shaft 20. The flexible shaft 20 iselectrically powered for high speed rotation to rotate the shaft 20 andtip 12 to break up plaque to treat stenosis of a vessel. A motor housing2, shown schematically in FIG. 13 , contains a motor mounted therein anda motor shaft (not shown). The atherectomy device 10 is operativelyconnected to the motor housing 2 such that activation of the motorrotates the shaft 20 of the device. A control knob can be provided toadjust the rotational speed of the shaft 20 and tip 12, and a window canbe provided to visually display the speed. Shaft 20 and tip 12 can bedisposable. In use, an introducer sheath or catheter is inserted throughan incision “A” in the patient's leg, and through an incision in thefemoral artery “B”. The catheter 24 with attached shaft 20 (positionedtherein) and tip 30 are thus introduced through the introducer sheath 35into the femoral artery “B”, and advanced to the target artery, e.g.,the coronary artery, to the treatment obstruction site. Note that aguidewire G extends through the shaft 20 and into the target artery sothat the shaft 20 and tip 12 are inserted over the guidewire. FIG. 13illustrates an exemplary introducer sheath 35.

The system in some embodiments further includes a vacuum source 5, shownschematically in FIG. 13 , communicating with the catheter 24 toaspirate particles from the catheter 24 in the space (lumen 27) betweenthe catheter 24 and shaft 20. Tubing 7 extends from the aspirationsource 5 to the catheter 24, through catheter hub 28, and in someembodiments through a side arm (not shown) in catheter hub 28. Thesystem in some embodiments can have an aspiration source 4 communicatingwith the introducer sheath 35 via hub 29, and in some embodimentsthrough a side port in hub 29, to provide aspiration in the spacebetween the sheath 35 and the outer wall of catheter 24. Note theaspiration through the introducer sheath 35, if provided, can be inaddition to the aspiration through catheter 24 or alternatively the solesource of aspiration. The system can also include a fluid source fordelivering fluids to the vessel. Tubing 11 extends from the fluid source6, through catheter hub 28, and in some embodiments through a side armin catheter hub 28, to communicate with the inner lumen of the shaft.

It should be appreciated that the device 10 is shown inserted throughthe femoral artery by way of example as other vessels can be utilizedfor access, such as the radial artery. Also, the tip of the presentinvention can be used to remove plaque or other obstructions in avariety of vessels such as the coronary artery, the tibial artery, thesuperficial femoral, popliteal, saphenous vein bypass grafts and instentrestenosis.

With reference to FIGS. 1-3 , the first embodiment of the atherectomytip of the present invention will now be described in more detail. Tipor burr 12 has a front (distal) portion (section) 14, a rear (proximal)portion (section) 16, and an intermediate portion (section) 18 betweenthe front and rear portions 14 and 16. These portions vary in transversecross-section as can be appreciated by the Figures. Thus, the frontportion 14 can be defined for convenience as the area starting at thedistalmost tip 17, forming a bullet nose configuration. Thecross-section of the front portion 14 in one embodiment is substantiallycircular in configuration. The intermediate portion 18 can be consideredas the region where the tip 12 transitions into the scalloped region 19.The cross-section of the intermediate portion 18 progressively changesfrom substantially circular, to an elongated shape having twosubstantially flat or linear opposing sidewalls 16 a. This can also beviewed as removed material from the otherwise conical shape so that thedistance between opposing linear walls 16 a is less than the distancebetween opposing walls 19 a.

Rear portion 16 can be considered to begin, for convenience, in thescalloped region 19, and terminate at the proximalmost edge 13 of tip12. The rear portion 16 preferably has the same elongatedcross-sectional dimension throughout its length, with substantiallylinear walls 16 a separated by a distance less than the distance betweenopposing walls 19 a.

The scalloped or narrowed section 19 is formed in both sides of the tip12 to reduce the profile of the tip 12. These scalloped sections formthe aforedescribed opposing substantially linear walls. By reducing theprofile, i.e., the diameter and circumference, the atherectomy tip ofthe present invention could be inserted through smaller introducersheaths than would otherwise be the case if the circumference increasedwith increasing diameter.

It should also be appreciated that the front, intermediate and rearportions/sections are designated for convenience and are not intended torequire three separate segments connected together. Tip 12 can be, andis preferably, a monolithic piece.

Tip 12 has a proximal or rear opening 32 and a distal or front opening34 connected by a lumen. The flexible shaft 20 extends through openings32, 34 and the lumen and is attached to the tip 12. In some embodiments,the tip 12 is attached such that the shaft 20 extends through frontopening 34 and extends a short distance distal of distalmost edge 17 oftip 12. Shaft 20 has lumen 25 dimensioned to receive a guidewire G toenable over the wire insertion of the atherectomy device 10.

The region of plaque removal is defined by the largest diameter regionof the tip since the tip is rotating at high speeds and the plaque iscut or abraded only where the tip comes into contact with it. However,the sheath size required is determined by the largest circumferenceregion of the tip. In certain embodiments, the region of plaque removalcan be further increased by altering the geometry and/or material of thetip 12 to create a wobbling effect which is described in more detailbelow.

As a result of the scalloped sections of the tip, as the diameter of tip12 increases in one orientation, it decreases in the transverseorientation, enabling the circumference to remain constant. Since thediameter is reduced in one transverse orientation, the tip 12 can beintroduced into an introducer sheath have an internal diameter slightlyless than the largest diameter of the tip, since the sheath has room todeform because of the reduced regions, i.e., the scalloped sections, ofthe tip 12. In the prior art elliptical tip, the rounded symmetricalconfiguration leaves no room for the sheath to deform so the sheath sizemust exceed the largest diameter region. Thus, the tip 12 of the presentinvention can fit into conventional introducer sheaths having aninternal diameter less than the largest outer diameter of the tip 12.This can be achieved by the fact that the tip 12 can deform the internalwalls of the sheath as it is inserted, by ovalizing the sheath. If thescalloped walls were not provided, the sheath would need to stretch,rather than ovalize to allow an oversized tip to pass.

Another way to view the tip 12 is that for a given catheter French sizedesired to be used by the surgeon, a larger atherectomy tip can beutilized if the atherectomy tip 30 of the present invention is selectedinstead of the prior art elliptical tip, thereby advantageouslyincreasing the region of plaque removal to create a larger passageway inthe vessel.

In alternate embodiments of the tip 12, longitudinal or elongatedcircular and oval cutting grooves could be provided to provide aroughened surface to cut or ablate the plaque as the tip is rotated. Thegrooves or indentations can be formed by laser cutting a series ofgrooves extending longitudinally within the interior of the tip stock.The tip is then ground to remove portions of the outer surface topartially communicate with the grooves, thereby creating indentationsforming a roughened surface for contact with the plaque. The resultingformation is a series of elongated cutouts/indentations on the front andintermediate portions and oval shaped cutouts/indentations on the distaland intermediate portions.

Another way contemplated to create the roughened surface is by blasting,e.g. sandblasting or grit blasting, the tip. The tip is held in afixture and blasted at a certain pressure, thereby removing portions ofthe outer surface to create a roughened surface. Creation of a roughenedsurface by chemical etching is also contemplated. In an alternateembodiment, an abrasive coating, such as diamond particles, is appliedto the tip.

FIG. 9 illustrates an alternate embodiment of the atherectomy tip. Inthis embodiment, the tip, designated generally by reference numeral 50,does not have scalloped sections but instead is substantiallycylindrical in configuration along its length except for the bullet nosetip. That is, it is circular in transverse cross-section throughout itslength. In all other respects, the atherectomy device of FIG. 9 is thesame as FIG. 1 , i.e., includes shaft 20 extending beyond theatherectomy tip, catheter 24, etc., so for brevity these components willnot be discussed herein since the discussion of these components withrespect to FIG. 1 are fully applicable to the embodiment of FIG. 9 .

In some embodiments, the tip 12 or tip 50 is symmetrical. In alternateembodiments, the outer geometry of the tip is symmetrical, however, aninner portion of one side of the tip is carved out or removed to createan imbalance resulting in an offset center of mass. This results inwobbling of the tip during high speed rotation which in turn enables aspinning diameter to exceed the cross-sectional dimension of the tip. Inthis manner, the tip can be used to remove plaque in a wider transversearea. This is shown in FIG. 3A with material removed from one side ofthe tip 12 to create a cutout or removed material section 15.

Removing material from one side of the tip is one way to achieve thiswobbling effect. Another way is through the tip itself being composed ofmaterials of different density, either the same material of differentdensities or different materials of a differing density such as in FIG.10B. Such materials utilized can include by way of example platinum andaluminum. These two ways of achieving the wobbling effect are alsodisclosed below in conjunction with the two piece tip.

As shown, the tip 12 is fixed to the shaft 20 and positioned distal ofthe end of the catheter 24. The shaft 20 is axially fixed withincatheter 24 but can rotate with respect to the catheter 24. The tip 12therefore remains distal of the opening 23 in the catheter 24 tomaintain the gap e.g., a fixed gap, between the proximal edge 13 of thetip 12 and the opening 23 so particles can be aspirated through theopening 23 and lumen 27 of the catheter 24.

In the alternate embodiment of FIGS. 11A and 11B, device 40 includes ashaft 42 having an auger or series of threads 44 proximal of tip or bit45. The auger 44 is positioned on the region of the shaft 42 proximal ofthe proximal edge 49 of tip 45 and extends along a length of the shaft42 within outer tube or catheter 47. These threads 44 function as anArchimedes screw, i.e., a screw pump, to remove the plaque. That is, asthe shaft 42 is rotated in the same manner as shaft 20, the screw'shelical surface scoops particles and directs the particles proximally(rearwardly) along the shaft 20 through the lumen of catheter 47. In allother respects, device 40 is identical to device 10. The auger 44 can beused in addition to an aspiration pump for aspirating particles into theopening 48 of catheter 47 (as in the embodiment of FIGS. 1-3 ) oralternatively used as a substitute so it provides the sole mechanism foraspirating particles through the lumen of the catheter 47. The auger 44can extend along the entire length or along a partial length of theshaft 20. The auger 44 for removing particles can be used with any ofthe atherectomy devices disclosed herein.

FIGS. 4-8, 10A and 10B illustrate alternate embodiments of theatherectomy tip of the present invention wherein the tip is composed oftwo separated components. More particularly, in the embodiment of FIGS.4-8 and 10A, the tip 60 of atherectomy device 61 has a first component62 and a second component 64. Tip 60 is mounted on shaft 70 (similar toshaft 20) at a position spaced proximally from the distalmost edge 72 ofthe shaft 70 so that a distal portion of the shaft 70 extends slightlydistally of the distalmost edge 65 of tip 60. Shaft 70 is rotatablymounted within lumen 82 of catheter 80 but axially fixed within catheter80 to create a fixed gap between the tip 60 and catheter 80. The shaft70 has a lumen for insertion over a guidewire G.

With reference to FIGS. 5-8 and 10A, tip component 62 has a cutout orremoved material portion 66 to reduce the amount of material of the tip.Tip component 64 does not have such cutout. In this manner, due to thematerial imbalance which creates an offset center of mass, the tip 60will wobble when rotated to remove plaque in an area greater than atransverse dimension of the tip 60.

In the embodiment of FIG. 10B, the two tip components 62′, 64′ havedifferent densities to achieve the wobbling effect.

Use of the atherectomy tip of the present invention is illustrated inFIGS. 12A-12D. The tip 60 of FIG. 4 is shown in these drawings, it beingunderstood that the other atherectomy devices and tips disclosed hereinwould be used in the same insertion and rotational manner. As shown inFIG. 12A, plaque “P” buildup on the interior wall of the vessel “V” hasoccluded the passageway through the vessel. Rotational shaft 70 withattached tip 60 (or tip 12 or any of the other tips disclosed herein) isinserted over guidewire G and by motorized rotation of flexiblerotatable shaft 70 is rotated at high speed in the direction of thearrow in FIG. 12B to remove plaque which comes into contact with itsouter surface. Aspiration is provided to aspirate the broken offparticles through opening 74 in catheter 72. The gap between the distaledge 75 of catheter 72 and the proximalmost edge 63 of tip 62 providesspace for the particles to be suctioned through opening 74. Thus, thecut plaque and debris can be removed from the patient's body as theparticles are dislodged by the rotating tip 60 as shown in FIG. 12C. Asthe plaque is removed, the device is continually advanced to continue toremove the plaque as shown in FIG. 12D. As noted above, an auger likeauger 44 can be provided in lieu of or in addition to an aspirationsource.

While the above description contains many specifics, those specificsshould not be construed as limitations on the scope of the disclosure,but merely as exemplifications of preferred embodiments thereof. Thoseskilled in the art will envision many other possible variations that arewithin the scope and spirit of the disclosure as defined by the claimsappended hereto.

What is claimed is:
 1. An atherectomy device for removing deposits suchas plaque from an interior of a vessel comprising: an outer memberhaving a distal end; a rotatable shaft positioned for rotationalmovement within the outer member and fixed axially within the outermember, the shaft having a longitudinal axis, a distal region and adistalmost edge; and a rotatable tip having a proximal end and a distalend, the proximal end of the rotatable tip positioned distally of thedistalmost edge of the outer member to create a gap between the proximalend of the rotatable tip and the distalmost edge of the outer member,the rotatable tip mounted to the distal region of the rotatable shaftand having a longitudinal axis and mounted to the rotatable shaft forrotation about its longitudinal axis upon rotation of the rotatableshaft, the rotatable shaft including a guidewire lumen for receiving aguidewire to enable over the wire insertion of the device.
 2. Theatherectomy device of claim 1, further comprising an auger positioned onthe rotatable shaft, the auger positioned proximally of the rotatabletip and extending along the rotatable shaft, wherein rotation of therotatable shaft rotates the auger to move particles macerated by therotatable tip proximally into the outer member.
 3. The atherectomydevice of claim 1, wherein particles are aspirated through the outermember in the space between the rotatable shaft and an inner wall of theouter member.
 4. The atherectomy device of claim 1, wherein therotatable tip is made of first and second materials, the first materialhaving a first density and the second material having a second densityless than the first density.
 5. The atherectomy device of claim 2,wherein particles are aspirated through the outer member in the spacebetween the rotatable shaft and an inner wall of the outer member. 6.The atherectomy device of claim 4, wherein the material of the firstdensity is on one side of the rotatable tip and the material of thesecond density is on the other side of the rotatable tip.
 7. Theatherectomy device of claim 1, wherein the rotatable tip has a firstregion on one side of a longitudinal axis of the shaft and a secondregion on an opposing side of the longitudinal axis of the rotatableshaft, and the first region has a cutout so a first amount of materialin the first region is less than a second amount of material in thefirst region.
 8. The surgical apparatus of claim 1, wherein therotatable tip is composed of first and second components, the first andsecond components radially spaced from each other.
 9. The surgicalapparatus of claim 8, wherein the first component is composed of amaterial having a density greater than the second component.
 10. Thesurgical apparatus of claim 10, wherein the first component has aportion removed so it is composed of less material than the secondcomponent.
 11. The surgical apparatus of claim 1, wherein the rotatabletip is positioned proximal of the distalmost edge of the rotatableshaft.
 12. An atherectomy device for removing deposits such as plaquefrom an interior of a vessel comprising: an outer member having a distalend; a rotatable shaft positioned for rotational movement within theouter member and fixed axially within the outer member, the shaft havinga longitudinal axis, a distal region and a distalmost edge; and arotatable tip having a proximal end and a distal end, the proximal endof the rotatable tip positioned distally of the distalmost edge of theouter member to create a gap between the proximal end of the rotatabletip and the distalmost edge of the outer member, the rotatable tipmounted to the distal region of the rotatable shaft and having alongitudinal axis and mounted to the rotatable shaft for rotation aboutits longitudinal axis upon rotation of the rotatable shaft, therotatable shaft including a guidewire lumen for receiving a guidewire toenable over the wire insertion of the device, the rotating tip having afirst portion and a second portion, the first portion being differentthan the second portion.
 13. The atherectomy device of claim 12, furthercomprising an auger positioned on the rotatable shaft, the augerpositioned proximally of the rotatable tip and extending along therotatable shaft, wherein rotation of the rotatable shaft rotates theauger to move particles macerated by the rotatable tip proximally intothe outer member.
 14. A method for removing deposits such as plaque froman interior of a vessel comprising the steps of: providing an introducersheath having an internal diameter; providing a deposit removal deviceincluding an outer member, a rotatable shaft and a rotating tip at adistal portion of the rotatable shaft, the rotating tip having a firstportion and a second portion, the first portion being different than thesecond portion, the rotatable tip having a transverse cross-sectionaldimension; inserting the introducer sheath through a skin incision andinto a vessel, advancing the rotatable tip adjacent the deposits to beremoved; and actuating a motor to rotate the rotatable tip at high speedto contact and remove the deposits, the tip rotating to remove depositsin a cross-sectional area greater than the transverse cross-sectionaldimension of the rotatable tip.
 15. The method of claim 14, furthercomprising the step of aspirating deposits through a space in the outermember between the rotatable shaft and an inner wall of the outermember.
 16. The method of claim 14, wherein the rotatable shaft has ascrew thread, and the step of rotating the rotatable shaft causes theexternal screw thread of the rotatable shaft to direct particlesproximally.
 17. The method of claim 14, further comprising the step ofapplying a vacuum to aspirate proximally deposits removed by rotationalmovement of the rotating tip.
 18. The method of claim 14, furthercomprising the step of inserting the tip over a guidewire.
 19. Themethod of claim 14, wherein first and second portions differ by thefirst portion having a cutout to remove material from the first portion.20. The method of claim 14, wherein the first and second portions differby the first portion having a first density and the second portionhaving a second density.